Wire winding machine



Sept. 24, 1963 c. T. JOHNSON ETAL 3,104,841

WIRE WINDING MACHINE Filed Oct. 10, 1960 2 Sheets-Sheet l INVENroRs Carl T. Johnson Ira E. Smith av KQ 224W/ Amm,

Sept. 24, 1963 c. T. .JOHNSON ETAL 3,104,841

WIRE WINDING MACHINE Filed Oct. lO, 1960 2 Sheets-Sheet 2 w w mmh A E t N\ whm 0 JS LE n a n BY Zman/ Mmmm! United States Patent O 3,104,841 WIRE WINDiNG MACHINE Cari T. .lohnsom New Providence, and Ira E. Smith, Lancaster, Pa., assignors to Radio Corporation of America, a corporation of Deiaware Filed 9ct. 1f), 1961i, Ser. No. 61,487 6 Claims. (Cl. 242-9) This invention relates to means for manufacturing sub-assemblies for electron discharge devices. In particular, this invention relates to a machine for manufacturing wound elements, such as filaments or grids, for use in an electron discharge device.

In certain high power, high frequency electron discharge tubes, the electro-des are arranged in a cylindrical structure including a co-axial stacked array of electrodes, with a heating filament or directly heated cathode being the innermost electrode.

In tubes of the type briefly 4described above, it has been found that, for high efiiciency operation, the filament is preferably of a type known as a basket weave filament. The basket weave filament comprises a wo-ven mesh screen of wire, such as thoriated tungsten wire. lIn order to provide an efficient basket weave type filament, the individual wires of the filament are'formed in a spiral in such a manner as to have a constant angle and constant pitch along the length of the filament. When an end of a filament is reached, the return angle and return pitch of the wire, as the spiral extends toward the opposite end of the filament, is also constant and equal to the forward angle and pitch. The reason for these requirements of constant angle and pitch of the filament wires is that the spacing between adjacent wires must be substantially constant in order to eliminate the possibility of having areas of the filament which are substantially hotter or substantially cooler than the balance of the filament. If any area of the filament is at a temperature that is substantially different from that of the balance filament, the electron emission from this area will also be substantially different. Variations in electron emission result in increased tube noise and decreased tube efficiency.

In the past, the basket weave type laments have been wound by hand in an attempt to accurately control the pitch and angle of the individual wires of the filament. The hand winding operation not only adds consider-able ,expensey to the filaments of this type, but also the hand weaving operation has proved to be inaccurate in that the operator can not accurately maintain the selected angle and pitch of the individual wires.

It is therefore an object of this invention to provide a novel machine for manufacturing an improved subassembly for use in an electron discharge device.

-It is another object of this invention to provide a new and improved machine that is capable of manufacturing accurately controlled basket weave type filaments.

These and other objects are accomplished in accordance with the general aspects of this invention by providing a machine including a carriage and a mandrel. The lament wire is clamped to the carriage and to the mandrel in such a manner that, when the mandrel is turned, the carriage moves toward the mandrel at a rate which will maintain the wire at a constant angle and pitch on the mandrel. Furthermore, the relative movement between the carriage and mandrel is such that the point of tangency of the wire on the mandrel moves steadily from one end to the other so that a uniform helix is formed. The carriage includes a wire clamping arm which is pivote-d to a position to wind a uniform helix in the opposite direction on the mandrel.

The invention will be more clearly understood by ACC reference to the accompanying two sheets of drawings, wherein:

FIG. 1 is a partial sectional View of a high frequency, high power tube of the type in which this invention is particularly useful;

FIG. 2 is a top view of a wire winding machine in v accordance with this invention; and,

FIG. 3 is a View inside elevation of the wire winding machine shown in FIG. 2.

Referring now to the drawings in detail, FIG. 1 illustrates a tube 10 of a type in which this invention is particularly useful. It should be understood, however that this invention can be utilized for manufacturing Sub-assemblies for other tube types, and the tube 10 is shown as a particular example of a tube type in which this invention is particularly useful. :'lhe tube 1t) comprises a cylindrical wire mesh type filament, or directly heated cathode, 12 that is supported between and fixed to two cylindrical filament terminals 14 and 16. Closely spaced around the filament 12 is an apertured control grid 1S. Because of this close spacing, the lament 12 must be accurately formed to prevent shorting between the control grid 18 and the filament 12. Surrounding the control grid 18 is an apertured screen grid 20. Positioned around the screen grid 20 is an anode 22 which may be cooled, during tube operation, by means of radiators 24. The tube 10 is an ultra high frequency, high power, lbeam tube and the details of tube construction may be found in a patent to Grifiith et al., Number 2,951,172. The structure which is of particular interest with respect to this invention is the basket weave filament or indirectly heated cathode 12.

It should be noted that the cathode or filament 12 is in the shape of an elongated cylinder and'is attached to filament terminals 14 and 16 which it surrounds. It should also be noted that the filament 12 includes a large plurality of spirals of a wire and the spirals have a constant pitch and constant angle from one end of the lament to the other as well as a constant pitch and constant angle in the opposite direction.

Referring now to FIGS. 2 and 3, there is shown applicants novel machine for manufacturing the filament 12 that is shown in FlG. 1. The machine generally comprises a carriage 26 and a mandrel 23. The mandrel includes an elongated mandrel cylinder 3f) which is of substantially the same diameter as are the filament terminals 14 and 16 shown in FIG. l. The mandrel cylinder 3f) is made of a material which can be processed along with the filament 12 and from which the filament 12 may be subsequently easily removed. One example of such material is Elkaloy manufactured by the P. R. Mallary Company. Positioned around the periphery of mandrel cylinder Sti and adjacent to opposite ends of the cylinder 3f? is a plurality of apertures each for receiving different mandrel pins 32 and 33. The mandrel pins are for the purpose of attaching the filament wire to the mandrel cylinder 30 at each change of direction of the wire in the filament. Connected to the mandrel cylinder 3ft is a means 34 for rotating the mandrel cylinder 3ft. The means 34 is shown as a hand operated wheel. However, if desired, a known machine drive (not shown) could be used to rotate the mandrel cylinder 3f). The mandrel cylinder Si) is fixed in position with respect to a table or work surface 36 by means of clamps 33 and 58. The clamps 38 and S8 maintain a periphery, in this case the upper periphery, in a predetermined plane with respect tothe work surface 36.

Positioned on the table 36 is a track 40 for the movement of the carriage 26 in the direction toward and away from the mandrel cylinder 3f). The carriage 26-includes a pivotable arm 42 and a wire clamp 44. The carriage a 26 is movable along the track from the position shown, to the end of the track di) which is adjacent to the mandrel 28. The limit of the movement of the carriage 26 is controlled, and adjusted, by means of an adiustable slider 46 which provides a starting point for carriage movement. A similar slider may be used for the stopping point of Vthe slider.

The arm 42 may be in either the position shown in full or the position shown in phantom. While in either posi tion, the arm 42 is in the same plane as the periphery of the mandrel cylinder Sti. ln other words, the arm 42 holds the wire in the plane of the upper periphery of the mandrel cylinder 3i).

The heating filament wire is held on a reel 48 which is loaded, so as to be under slight tension, by any conventional means such as a spring (not shown). The wire 52 is fed from the reel to the clamp 4d to which it is lixed by tightening the latter, and to the mandrel 3i? where it is also fixed, by being twisted around one of the pins 32.

When a wire 52 is twisted or looped around a pin 3f., the carriage is positioned in its most remote position from the mandrel, i.e. against the slider d6, and the clamp 44 is tightened on the wire while the carriage is in this position. Then, by rotating the mandrel 2t?, the wire 52 is wound onto the mandrel c linder 3d to form a uniform helix around the mandrel cylinder. As the wire is wound on the cylinder 36, the pull ot the wire overcomes a weight Sti, or similar loading means, and moves the carriage 26 toward the mandrel cylinder 3i?. When the carriage 26 strikes the other extreme of its movement, a complete helix of wire has been wound on the mandrel Sil. The complete helix may include any selected number of turns of the wire 52.

At this time, the wire 52 is looped over a pin 33, the position of the arm d2 is reversed, i.e. pivoted or rotated to the phantom position (FG. 2), the clamp d4 released and carriage 26 is returned to its starting position, ie. abutting slide d6. The clamp dd is again fixed to the wire 52 and the mandrel 2S is again rotated in the same direction. This rotation again moves the carriage toward the mandrel and provides a helix of the same pitch and Wire angle as has been wound on the mandrel cylinder 30 but in the opposite direction. When the helix is completed,another mandrel pin 32 is inserted in a proper location, the carriage 26 returned to the starting position, the arm 42 rotated, the carriage clamped by clamp de to the wire, and the process is repeated until any selected number of helices is provided on the mandrel 3d.

In utilizing this invention, a iilarnent 1.2 may be made in any selected diameter by changing the diameter of the mandrel cylinder 3l). Also, the length, pitch, wire size, wire angle and number of wires can be varied by varying the distance the carriage travels, the diameter of the mandrel 3Q, and the spacing between pins 32, 33 of the mandrel.

The wire 52 observes a constant angle with respect to the axis of the mandrel 3i) during rotation of the latter, to provide a uniformity in the pitch of the wire turns around the mandrel. This is most conveniently explainable by considering an analogy wherein the arm 42 is iixed and the mandrel is movable on track All@ towards arm 42 during a winding operation. l'n this analogy, it is obvious that the angle between wire 52 and the axis of mandrel 3i) is constant during the winding operation.

When theV Winding or a desired number ot helices is completed, the wire 52 is cut, the mandrel is detached from the base 36 and placed on a roller Welder (not shown). The various wires of the filament structure 12 are then welded together and are removed from the mandrel 39 when the pins 32 and 33 are removed. The helix or iilament 12 is then ready for further processing such as lcoating with electron emissive material, e.g., and other manufacturing steps.

This invention is applicable to any selected Vwire diameters, ilarnent lengths, filament diameters, turns per lilai 4 i ment, pitch of the helix and angle of the wires. Also, this invention may be used to manufacture a filament for any selected tube type and the tube shown in FlG. l is merely an example. By means of this invention, filaments can easily1 be manufactured having a uniform pitch, Vwire spacing, diameter and other desirable characteristics.

What is claimed is:

l. A winding machine comprising an axially rotatable cylindrical mandrel having one end portion adapted to hold one endoi' a Wire, a carriage for holding a portion ofy said wire spaced from said one end thereof, said carriage being mounted in right angular movable relationship with respect to an intermediate portion of saidmandrel, said carriage `having an arm extending parallel to the mandrel axis, said arm `including aportion olset to one side of a transverseplane through the longitudinal-center of said mandrel, said arm portion having means for securing thereto said wire portion, said one end portion of the mandrel being olset to the opposite side `of said plane and means for axially rotating said mandrel and simultaneously moving said carriagey toward said mandrel-.in

said right angle relationship, whereby the angle of saidwire with respect to the axis of said mandrel is maintained constant asa result of the :movement of said carriage.

2. A'machine for winding a sub-assembly lfor an electron discharge device comprising a fixed surface, a cylindrical mandrel rotatably mounted on said surface, a longitudinal periphery of said cylindrical mandrel delining a straight line extending parallel to the mandrel axis and disposed in a predetermined plane, an arm for holding a wire, said arm being pivotally mounted so as to be positioned to one side of a plane transverse of said manthe outer end portion of said mandrel, and means for` rotating said mandrel on its axis, whereby said carriage moves toward said mandrel by the resultant pull of Vsaid wire.

3. A machine for winding a basket weave type lila.-v

ment said machine comprising a horizontal support member, means for positioning an elongated mandrel cylinder in axially rotatable relationship on said support memer, so that a portion of the periphery of saidA cylinder delines a straight line `disposed in a predetermined plane,

a carriage supported on said supportmember and'nV movable relationship toward and away from said straight line in ya path extending at right angles to said line, means for positioning said carriage in a position remote from said mandrel, a pivotable arm mounted on said carriage,

means on said arm for holding wire, said arm being adapted to -be positioned successively, laterally adjacent to opposite end portions of said mandrel and in said predetermined plane for successively disposing said holding means to the two sides of a vertical plane through the longitudinal center of said mandrel, means for clamping a wire on one of said end portions of said mandrel remote from said aim, and means ltor axially rotating said mandrel so that said wire pulls said carriage toward said mandrel at a rate related to the speed of rotation of saidv mandrel and said Wire forms a helix around saidmandrel when said one of said end portions of the mandrel andA said holding means on said yarm are ron lopposite sides of said plane.

4. A winding machine comprising an elongated axially rotatable cylindrical mandrel having means on a peripheral portion thereof adapted to hold a portion of a wire work piece, a carriage movable towards said mandrel in` a path normal to the mandrel axis, said carriage having an armextending in a direction from said carriage normal to said path, said arm having means adapted to hold another pontion of said Wire work piece, said second named means being spaced from a plane normal to said mandrel and passing through said peripheral portion thereof, means for axially rotating said mandrel whereby said carriage is adapted to lfeed said wire to said mandrel when the mandrel is axially rotated, for providing thereon a Wire helix of uniform pitch.

5. A Winding machine comprising an elongated axially rotatable circularly cylindrical mandrel having holding means thereon for holding a wire alt one point of the wire without slipping, feeding means for holding the wire at another point of the wire without slipping said holding means being spaced in a direction axially of said one point of the Wire and radially from the mandrel means for rotating said mandrel about its axis, said feeding means and said other point being constrained for movement toward said mandrel in a path normal to the mandrel axis in lresponse to rotation of said mandrel, and means for urging apart said mandrel and said feeding means whereby as said mandrel rotates a wire held by said holding means and said feeding means respectively at said points is placed under tension to be drawn out substantially in a straight line and the feeding means is drawn toward the mandrel by the wire asthe wire is wound on the mandrel and the wire is thereby Wound on the mandrel with a constant pitch.

6. A Wire winding machine comprising a support member, an elongated mandrel cylinder, means for positioning said mandrel cylinder `on said support member so that said cylinder may be axially rotated, means adjacent to one end lof said mandrel cylinder for holding an end portion of a wire, a carriage, means mounting said carriage on said support member so that said carriage may be moved towardand away from the axis of said mandrel cylinder in a path normal to said axis, means for normally maintaining said carriage in a position remote from said mandrel cylinder, a wire holding arm extending parallel to said mandrel cylinder, means mounting one end of said arm on said carriage so that the other end of said arm may be positioned adjacent to either end of said mandrel cylinder, and means for rotating said mandrel about the cylinder axis with said arm positioned adjacent to the other end lof said mandrel cylinder so that said carriage moves toward said mandrel cylinder and said Wire and said mandrel cylinder describe an angle 0f less than 90.

Heckman et al. Mar. 25, 1952 Trotta Aug. 2, 1960 

4. A WINDING MACHINE COMPRISING AN ELONGATED AXIALLY ROTATABLE CYLINDRICAL MANDREL HAVING MEANS ON A PERIPHERAL PORTION THEREOF ADAPTED TO HOLD A PORTION OF A WIRE WORK PIECE, A CARRIAGE MOVABLE TOWARDS SAID MANDREL IN A PATH NORMAL TO THE MANDREL AXIS, SAID CARRIAGE HAVING AN ARM EXTENDING IN A DIRECTION FROM SAID CARRIAGE NORMAL TO SAID PATH, SAID ARM HAVING MEANS ADAPTED TO HOLD ANOTHER PORTION OF SAID WIRE WORK PIECE, SAID SECOND NAMED MEANS BEING SPACED FROM A PLANE NORMAL TO SAID MANDREL AND PASSING THROUGH SAID PERIPHERAL PORTION THEREOF, MEANS FOR AXIALLY ROTATING SAID MANDREL WHEREBY SAID CARRIAGE IS ADAPTED TO FEED SAID WIRE TO SAID MANDREL WHEN THE MANDREL IS AXIALLY ROTATED, FOR PROVIDING THEREON A WIRE HELIX OF UNIFORM PITCH. 